I dont know if Im allowed to plug a company here, if not, I appologize. This guy boasts that his slugs can maintain a 4 in pattern at 200 yards. A little pricey for me. Check it out http://www.nitrocompany.com

Also, I have heard nothing but good things about brenneke slugs. I havent tried them yet, but I just got a new gun and plan on sighting it in with those. I hear they kick like a mother, but they have some serious knock down power.